The invention concerns a fuel delivery system for an internal combustion engine operated with a gasoline/alcohol mixture as fuel. The system includes a fuel pump for supplying fuel under pressure from a fuel tank to the fuel feed device of the engine.
It is known to operate internal combustion engines, in particular automobile engines, with a gasoline/alcohol mixture in place of gasoline. Mixtures of gasoline and methanol or ethanol have been used for example. When such a fuel mixture is employed, it is found that in the presence of water, and especially at low temperatures, the components of the fuel mixture may disassociate or separate. Such a separation deleteriously affects the operating behavior of the internal combustion engine because the fuel feed device of the engine, such as the carburetor or the fuel injection device, is adjusted for a prescribed fuel composition and if this composition is changed, the feed device is no longer able to produce a fuelair mixture corresponding to the prevailing operating conditions of the engine.
The introduction of water in liquid or vapor state into the fuel tank cannot always be avoided with certainty since it may occur during filling of the automobile tank or even during operation by way of the vent line. Therefore, separation of the fuel mixture entailing the consequences described above may occur.
Therefore, it is an object of the present invention to provide a fuel delivery system which is operative to supply a uniform gasoline/alcohol mixture to an internal combustion engine and to prevent as much as possible the separation, possibly caused by the presence of water, of the gasoline/alcohol mixture in the fuel tank.